The literally iron-fisted headmistress of Gravedale High, the school for monsters in the short-lived 1990 animated series of the same name, mainly remembered for starring Rick Moranis as the main character. Trained from screencaps of the best quality video I could find, which wasn't great.

Tags are: "HM_Crone, blue hair, blue skin, yellow eyes, metal left hand". Her outfit is "Purple jacket, white blouse, earrings, white cuffs, bow, belt, purple skirt, high heeled boots".